Air conditioning



Feb. 28, 1967 c. L. TUCKER AIR CONDITIONING Filed May 18, 1965 I Illlllllll all L w b m, 4 2 4 3 7 4 l S R MY r 0E T w N R v M .w I MT v nWA m C .5 M

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United States Patent 3,306,348 AIR CONDITHONING Carl L. Tucker,Skaneateies, N.Y., assignor to The Singer Company, New York, N.Y., acorporation of New Jersey Filed May 18, 1965', Ser. No. 456,790

9 Claims. (Cl. 165-42) This invention relates to air conditioning, andmore in particular to air conditioning systems for buildings or forrooms or other zones or spaces.

An object of this invention is to provide an air conditioning system fora multiple space or zoned building or a part thereof. A further objectis to provide an air conditioning system which is versatile and whichmay be operated efficiently to condition the air in the various rooms orspaces individually, and without the operation in one room or spaceinterfering with the operation else where. A further object is toprovide a cooling and ventilating system of the above character. Afurther object is to provide a system of the above character where thereis central control by which all of the units of the system may bestarted and stopped, and yet where the individual units may be operatedindependently. Another object is to provide an air conditioning systemhaving individual units within the various zones or spaces and a centralcontrol by which the units may be started in a controlled sequence andwhich insures against unnecessary operation of any of the various units.These and other objects will be in part obvious and in part pointed outbelow.

In large office buildings and in multiple unit living quarters, it isdesirable to provide considerable leeway in the relative amounts of airconditioning which is provided in various spaces or zones. There may beextreme differences in the heating and cooling loads and the occupantsmay desire different temperature conditions. Furthermore, when one spaceor zone is unoccupied, it may be desirable to discontinue the operationof the air conditioning facility for that space or zone. The presentinvention provides for such control. Furthermore, the system permits anyor all of the air conditioning facilities to be started and stopped inaccordance with any desired program. Also, the system may be left in acondition so that air conditioning is provided only in the spaces orzones where the occupants desire it, but is immediately available in allof the spaces or zones.

In the drawing:

The single figure is an abbreviated and schematic representation of anair conditioning system comprising one embodiment of the invention.

Referring to the drawing, the system is illustratively formed by a largenumber of identical self-contained air conditioning units. However, forpurposes of understanding the invention, it is necessary to illustrateonly three of these units in the drawing and the showing has beenlimited in that manner to avoid unnecessary complications andrepetition. The three air conditioning units 2, 4 and 6, which are shownwith their casings represented in broken lines, are located in differentrooms of a building, and each of them is positioned at a window so as touse outside air for cooling and for ventilation, and so as to cool theroom where the unit is located. These units receive electrical currentthrough a pair of power lines 8 and 10 which extend from a mastercontrol switch 12. The master control switch and the other components ofthe system which are shown, are presented schematically in the drawing,and it is understood that other equivalent switches and additional orother components are used in the actual commercial construction.

The air conditioning units 2', 4 and 6 are identical and unit 2 will bedescribed. Air conditioning unit 2 has a refrigeration system or unit 11which comprises a motor: compressor 14, a condenser 16, a receiver 18,an expansion valve 2%, an evaporator 22, and standard thermostatic andsafety controls. A fan 24, driven by a motor 26, directs air over thecondenser, and a fan 28, driven by a motor 3% directs air over theevaporator. This entire refrigeration system and the controls areenclosed within a casingin-dicated in broken lines at 32. As has beenstated above, the unit is positioned at a window or an opening in theoutside wall so that outside air is drawn in by the fans for ventilationof the room and for cooling the compressor and the condenser, and fan 28circulates the air over the evaporator for cooling the room. Thecirculation of air by fan 28 involves recirculation of a substantialamount of the air in the room, but fresh air is drawn in as desired. Anair filter is provided for the air passing through the evaporator, andother components and controls are provided as desired.

Air conditioning unit 2 includes internal power lines 36 and 38 to whichpower is supplied to operate the unit through a manual control switch34, in a manner discussed below. The manual control switch 34 is formedby a pair of switch units 31 and 33 which are closed when the occupantof the room or zone desires air conditioning. Line 38 extends fromswitch unit 33 directly to the motor compressor 14 and the fan motors 26and 30. Line 36 extends from switch unit 31 to a normally open,camoperated switch 46 the other side of which is connected through aline 47 to the motor compressor 14 and the fan motors 26 and 30. Hence,when power is supplied to lines 8 and 10 and switches-34 and 46 areclosed, the unit 11 is operated either continuously or under the controlof automatic thermostat controls.

The normally open switch 46 is closed by the operation of a timer motorand cam unit 48 formed by an electric motor 52 and a cam 54 driventhereby through a gear reduction and clutch assembly 56. Cam 54 is shownin its home or rest position to which it is returned automatically by aspring 49 whenever motor 51 is de-energized. However, when power issupplied to motor 51 the motor operates through assembly 56 to drive cam54 clockwise from the position shown through an arc of the order of 300where it is stopped and held as long as motor 51 remains energized.Assembly 56 includes a release clutch which permits the cam to be heldin either its rest position or the position at the end of its clockwisemovement.

A bimetallic strip 50, having an electric heater 52 is mounted at itslower end with its upper end adjacent cam 54. Heater 52 controls thetemperature of strip 50 and causes it to move between the position shownin full lines when it is heated and the position shown in broken lineswhen it is at room temperature. When in the heated position, the upperend of strip 50 is positioned to engage with a ledge 53 upon cam 54 andto thereby latch the cam from clockwise movement away from its home orrest position. However, when the bimetallic strip is at room temperatureit is out of the path of movement of the cam so that the cam is rotatedfreely by the energization of motor 51. Heater 52 is connected directlyacross lines 8 and so that it heats strips 50 and moves it to thecam-latching position whenever the system is supplied with power.However, for purposes to be discussed below, a push-button plunger 44 isprovided which projects from the! cabinet and is pressed to move thebimetallic strip 50 from its full line position toward the broken lineposition and thereby release the latching engagement of the strip withthe cam.

Normally open switch 46 is formed by a contact 64 and a flexible contactarm 60, which has a switch contact at its lower end and which carries acam follower 62 riding upon cam 54. When cam 54 turns clockwise, arm 60is swung to the right against contact 64, thus to close the switch.Contact 64 is mounted upon a flexible spring arm 66 which may be swungto the left from the position shown by an adjusting screw 68. Hence, theposition of contact 64 may be changed by adjusting screw 68 so as toregulate the distance which arm 60 must be moved by cam 54 so as toclose switch 46. The clockwise movement of cam 54 is at a constant rateso that the adjustment of the position of contact 64 determines thelength of time which elapses between the start of the turning of the camand the closing of switch 46. As will be discussed below this adjustmentis used to regulate the timing for the starting of the various airconditioning units in the system so as to avoid simultaneous starting.Timer motor 51 is connected at one side directly to line 8 and at theother side through a normally closed switch 70 to line 10. Switch 70 hasa push button 72 which projects from the cabinet and may be pressed tode-energize motor 51 and thereby cause cam 54 to return to its restposition, as will be discussed below.

When power is supplied to lines 8 and 10 by the closing of switch 12 thetimer motor 51 in each of the units 2, 4 and 6 is energized. Assumingthat all of the switches 34 are closed and that the power has beendisconnected for a sufficient period of time for the bimetallic strips50 to be at room temperature and in the broken line position, each ofthe timer cams 54 is free to turn and starts to turn clockwise from itsrest position. The adjustments of the various switch contacts 64 is suchthat the air conditioning units are started in accordance with apredetermined sequence, thus avoiding an excessive current surge. Theair conditioning units then continue to operate in accordance with thetemperature demands in their various rooms or zones and may be startedand stopped by their automatic controls.

The invention contemplates that it is desirable at times to stop all ofthe air conditioning units, but to permit the occupants of the variousrooms or zones to restart their units individually. For example, asdiscussed above, most of the occupants of an office building may leavethe premises at the end of the working day, but it is desirable topermit the remaining occupants to start their air conditioning units ifthey wish. Accordingly, at the end of the day, or at such other time asit is desirable to do so, power is momentarily disconnected from lines 8and 10 so asto de-energize each of the timer motors 51, and each of thecams is returned automatically to its rest position, as represented inthe drawing. That opens the various switches 46 and stops all of the airconditioning units. However, in the meantime, each of the heaterelements 52 has heated its bimetallic strip 50 so that the strip is inthe full-line position. Therefore, when each of the cam 54 returns toits rest position, its bimetallic strip latches and holds the cam fromturning. When power is restored to lines 8 and 10 after only themomentary discontinuance, strips 50 have not cooled off and each of thetimer motors 51 is restarted, but the bimetallic strips hold each of thecams 54 in its rest or open-switch position. The characteristics of unit48 are such that the slip clutch of assembly 56 permits the timer motorto run freely. Hence, the various switches 46 remain open and their air.conditioning units 11 are not restarted as long as the cams are. heldfrom movement by strip 50. With the system in this condition the systemdoes not provide air conditioning. However, if any person within any ofthe rooms or zones desires air conditioning he may immediately press hispush button plunger 44 so as to manually move the bimetallic strip tothe broken-line position out of latching relationship with its cam. Thatwill permit the cam to start its rotation, and it is turned in thenormal manner so as to close its switch 46 and start the operation ofthe air conditioning unit. The operation normally continues until poweris again disconnected from lines 8 and 10. However, the person in theroom may open the manual switch 34 to stop the unit at any time. Theopening of the switch 34 of an air conditioning unit renders that unitinoperative even though power is shut off from lines 8 and 10 for asufficient time to permit the bimetallic strip 50 to return to roomtemperature. However, if the occupant or operator wishes to stop a unitwhich has been started by pressing the push-button plunger 44, he maypress the push button 72 to momentarily open switch 70. That actiondisconnects the power to motor 51 so as to permit the cam 54 to returnto its rest position in the same manner as when switch 12 is openedmomentarily. Thus, the operator or the occupant is provided with manualcontrol to start and stop the air conditioning unit as he wishes, and hemay also restore the circuit to the stand by condition, after the unithas been started by pressing the push button plunger 44.

The illustrative embodiment of the present invention has an additionalimportant feature, namely, the switches 46 are adjusted to give apredetermined sequence to the starting of the various air conditioningunits after they have all been shut down for a period of time. Thesequence starting of the units distributes the peak starting currentloads over a suflicient time to prevent overloading of the electricalcircuit, but these peak current loads are of very short duration, andthe staggered starting does not make any perceptible change in the timeof starting the various air conditioning units. Nevertheless, verysubstantial benefits are derived, as compared with a system where all ofthe starting switches would be closed at exactly the same instant.

The present invention contemplates the momentary disconnecting of theelectrical power to the system so as to stop the various units of thesystem, and it has been indicated that this can be done manually atselected times. The invention also contemplates that this power disconnecting operation may be carried on automatically, for example, by aprogram switch unit. Accordingly, in the drawing, master control switch12 is of the solenoid type, with a solenoid 124, and a manual switch 127which is closed to energize the solenoid to close switch 12 manually.However, in order to provide automatic operation, solenoid 124 includesa normally opened push-button switch 126, and a normally closedpush-button switch 128. The closing of switch 12 connects line 8 and 10respectively to power lines 130 and 132. Solenoid 124 is connected atone side to line 132, and the closing of switch 126 connects the otherside of the solenoid to line 130. An interlock circuit to solenoid 124is also provided by a line 134 which extends from line 8 through thenormally closed switch 128 to solenoid 124. Switch 12 is normally urgedtoward its open position by a spring 136. A normally closed switch 125in series with switch 126 may be opened to disconnect the automaticprogram circuit.

The momentary closing of push-button switch 126 energizes solenoid 124,and closes the master control switch 12. The switch is then held closedby the interlock circuit formed by switch 128 and line 134. The openingof switch 128 breaks the interlock circuit and de-energizes solenoid124, and switch 12 reopens automatically. Con nected across lines 130and 132 is an adustable timer 138 which has a cam shaft upon which twocams 140 and 142 are mounted. When the cam shaft is rotated by timer138, cam 142 first moves into engagement with switch 128 and opens thisswitch, and then after a short interval of time cam 140 moves againstand closes switch 126. Hence, one complete revolution of the cam shaftopens the master control switch 12 and then recloses it after apredetermined period of time. This period of time is sufiicient topermit the cam 54 of each of the various air conditioning units toreturn to its rest position so that its switch 46 is opened.

Timer 138 may be adjusted to turn its cam shaft a complete revolution atthe end of any predetermined period of time, or at predeterminedintervals in accordance with a program. Therefore, with the timeroperating continuously, the cam shaft remains stationary except at thepreselected times of the day when it is determined that the powercircuit should be opened. For example, with the arrangements discussedabove, the suggested manual opening and closing operations of the mastercontrol switches are performed in accordance with a predeterminedsetting of timer 138. This may include the opening of switch 12 at 8p.m., and at every four hours thereafter as long as the building isoccupied during the evening and over weekends.

It will be understood that the invention is applicable to systems otherthan the one represented in the drawing, and particularly to systemsincorporating additional features and characteristics. In theillustrative embodiment, the refrigeration means at each zone or room isa selfcontained unit, but it is understood that other air conditioningmeans, such as heat exchange coils and induction and fan-coil units, maybe used while still attaining certain advantages of the invention. Thepower supply and control circuit provides remote control for the basicoperation, and yet permits the occupants to exert control upon theindividual air conditioning units. Also, thermostatic controls provideautomatic operation, particularly where manual control is not fullysatisfactory.

Under some circumstances the power for operating the air conditioningunits 11 is supplied from power lines which also supply power to otherequipment. In such cases, the power is supplied to the timer motors 51and the heaters 52 through a separate control circuit. Also the airconditioning units may be supplied with power from a tour-wire,three-phase circuit having a neutral line. In such cases the power forthe timer motors 51 and the heaters 52 may be supplied through theneutral line and one of the other lines.

As many possible embodiments may be made of the mechanical features ofthe above invention and as the art herein described might be varied invarious parts, all without departing from the scope of the invention, itis to be understood that all matter hereinabove set forth, or shown inthe accompanying drawings is to be interpreted as illustrative and notin a limiting sense.

I claim:

1. In an air conditioning system, the combination of: power supply meansconstituting a supply of electric power; an air conditioning unit whichis adapted to change the temperature of air flowing through it and whichincludes electrical means which renders it operative when connected tosaid power supply means; and a switch assembly connected to receivepower from said power supply means and adapted to be closed and therebycomplete an electric circuit to said air conditioning unit, said switchassembly comprising, a normally open switch, and a cam which is adaptedto be turned from a rest position to close said switch, a timer motorwhich is connected to said cam and is operative to turn said cam fromsaid rest position to its switch-closing position, latch means having alatch portion which has a latching position wherein it engages said camand holds said cam from moving from said rest position and aninoperative position wherein said cam is free to move, andlatch-releasing means which is positioned relative to said latch meanswhereby it may be operated manually to move said latch means to saidinoperative position, said latch means including temperature responsivemeans which is operative to move said latch portion from saidinoperative position to said latching position upon a predetermined risein temperature, said switch means including means to heat saidtemperature responsive means when power is supplied thereto.

2. Apparatus as described in claim 1 wherein said latch means is abimetallic strip rigidly mounted at one end and having its other endforming said latch portion and adapted to swing between said latchingand inoperative positions, and wherein the means to heat said latchmeans is an electric heater positioned adjacent said bimetallic strip.

3. Apparatus as described in claim 2 wherein said latch-releasing meansis a push button plunger positioned to engage said bimetallic strip.

4. Apparatus as described in claim 3 wherein said timer motor operatesat a predetermined speed, and wherein said switch is adjustable tocontrol the time between the statring of the movement of said cam andthe closing of the switch.

5. An air conditioning system comprising a plurality of units each ofwhich comprises the combination as described in claim 1, and commonpower supply lines which are connected to operate all of said airconditioning units and all of said switch assemblies.

6. Apparatus as described in claim 5 which includes a timer switchassembly which is adapted to disconnect and connect power to said commonpower supply lines.

7. In an air conditioning system for maintaining various zones of abuilding at individually selected temperatures, the combination of: aplurality of separate airconditioning units; power means constituting anelectric power supply for said units; and a control system including aplurality of switch assemblies associated respectively with said units,each of which comprises a unit-control switch and is connected to saidpower means, timer motor-cam means including a cam and means to turnsaid can from a rest position to close said unit-control switch, latchmeans which is moved during the operation of the unit to and from aposition to latch said cam in said rest position, and latch controlmeans to render said latch means ineffective after said timer motor-cammeans has been inoperative for a substantial period of time and torender said latch means efiective after said timer motorcam means hasoperated for a period of time, and manual means to release said latchmeans.

8. In an air conditioning system for maintaining the desired temperaturethrough-out a building, the combination of, a plurality of separateunits each of which is opereable to change the air temperature flowingthrough it, and a power supply and control system comprising meansconstituting a supply of power for said units and to connect anddisconnect said supply, said power supply and control system including aplurality of control assemblies associated respectively with said unitsand each including unit-control switch means which is opened and closedto stop and start its unit when power is supplied thereto and a timeroperating unit which is operable upon the initial supplying of power tothe unit to close its unit-control switch means, each of said controlassemblies being constructed and arranged to open its unit-controlswitch upon each discontinuance of the supplying of power thereto andlatch means which includes a latch portion and latch operating means tomove said latch portion, said latch-operating means being operative inaccordance with a timed cycle to move and said latch portion from aninoperative rest position to an operative latching position apredetermined time after power has been supplied to the control assemblyand to return said latch portion to said inoperative rest position onlyafter power has been discontinued for a predetermined period of timewhereby References Cited by the Examiner UNITED STATES PATENTS 2,561,0677/1951 Newton 165-12 2,801,825 8/1957 Bishofberger 165-12 3,037,3646/1962 Tucker et al. 62158 3,058,724 10/1962 Maudlin 165-27 X MEYERPERLIN, Primary Examiner.

ROBERT A. OLEARY, Examiner.

M. A. ANTONAKAS, Assistant Examiner.

7. IN AN AIR CONDITIONING SYSTEM FOR MAINTAINING VARIOUS ZONES OF ABUILDING AT INDIVIDUALLY SELECTED TEMPERATURES, THE COMBINATION OF: APLURALITY OF SEPARATE AIRCONDITIONING UNITS; POWER MEANS CONSTITUTING ANELECTRIC POWER SUPPLY FOR SAID UNITS; AND A CONTROL SYSTEM INCLUDING APLURALITY OF SWITCH ASSEMBLIES ASSOCIATED RESPECTIVELY WITH SAID UNITS,EACH OF WHICH COMPRISES A UNIT-CONTROL SWITCH AND IS CONNECTED TO SAIDPOWER MEANS, TIMER MOTOR-CAM MEANS INCLUDING A CAM AND MEANS TO TURNSAID CAN FROM A REST POSITION TO CLOSE SAID UNIT-CONTROL SWITCH, LATCHMEANS WHICH IS MOVED DURING THE OPERATION OF THE UNIT TO AND FROM APOSITION TO LATCH SAID CAM IN SAID REST POSITION, AND LATCH CONTROLMEANS TO RENDER SAID LATCH MEANS INEFFECTIVE AFTER SAID TIMER MOTOR-CAMMEANS HAS BEEN INOPERATIVE FOR A SUBSTANTIAL PERIOD OF TIME AND TORENDER SAID LATCH MEANS EFFECTIVE AFTER SAID TIMER MOTORCAM MEANS HASOPERATED FOR A PERIOD OF TIME, AND MANUAL MEANS TO RELEASE SAID LATCHMEANS.